!Mayday!, ‘!Mayday!’ (Southbeat)

Powered by a frenetic go-go beat, a warm, raspy hook (courtesy of Cee-Lo), and a clever YouTube marketing scheme, Mayday’s first single, “Groundhog Day,” became a left-field internet hit. The duo’s debut album isn’t quite as infectious. Their defiantly old-school beats, dark, slinky keyboard melodies, and MC Bernbiz’s forceful, if not particularly fluid, rhymes don’t always click. But when they do, the results can be memorable enough to make you forget about the lulls.